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This study examined the corrosion inhibition of 304 stainless steel (304 SS) with fucoidan in 3.5% NaCl solution using both chemical and electrochemical methods, including mass loss as a chemical method and electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PP) as an electrochemical method. The fucoidan compound was verified and characterized by Fourier-transform infrared spectroscopy (FTIR), ultraviolet–visible spectroscopy, and morphology characteristics. The PP curves indicate that fucoidan was an effective corrosion inhibitor for 304 SS in 3.5% NaCl solutions, which indicates that the compound is a mixed-type inhibitor. It was shown that by adding the fucoidan inhibitor, the corrosion potential (Ecorr) and Tafel lines were slightly shifted. With the compound added, the value of the double-layer capacitance was reduced. In the case of 200 ppm, it reached maximum efficiencies of 81.7%. After studying its adsorption behavior on 304 SS, the Langmuir isotherm and chemical adsorption were concluded. It was necessary to compare the theoretical computations with the experimental findings using both density functional theory (DFT) and Monte Carlo simulations (MC). [ABSTRACT FROM AUTHOR]

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The formulation of ultra-high-performance concrete necessitates the use of a high cement content. The alkaline nature of cement makes it susceptible to acid attacks. In addition, its high C3A content causes its vulnerability to sulfate attack under the development of expansive ettringite, where porosity plays an important role. The main objective of this study was to figure out how mass loss and dimensional instability affected the rate of reaction and its relationship to acid concentration. It is noted that in contrast to sulfuric acid attack, sulfate attack on ultra-high-performance concrete (UHPC) is characterized by the accumulation of sulfate ions near the surface until reaching a critical concentration known as the threshold value. However, the reaction effect was not remarkable, as attributed to the extremely low porosity. The effect of curing was found to have a minimal influence on acid resistivity because it is a kind of spontaneous acid-base reaction that cannot be alleviated. In this research work, the UHPC's service life can be predicted when exposed to different concentrations of sulfuric acid. When comparing acid and sulfate attacks, the latter becomes negligible. Despite the use of silica fume and fly ash, the reactivity with sulfuric acid was found to occur spontaneously and rely on cement content and acid concentration. A concentration of 2.5% sulfuric acid is the threshold concentration after which a substantial change in the development of strength takes place. Both reactions were monitored on different types of samples over time using several techniques, such as XRD, TGA, and DSC and optical microscopy. [ABSTRACT FROM AUTHOR]

Erosion behavior at the interface of different layers is a critical consideration in pavement design and construction. Especially, this issue poses a particular challenge in dispersive clays, which are prone to excessive erosion. The current paper focuses on evaluating the effectiveness of nanoclay in stabilizing and mitigating the contact erosion behavior of dispersive clays. To do so, a range of experimental testing, including double hydrometer, pinhole, contact erosion and unconfined compressive strength (UCS) tests was employed. The findings revealed that incorporating 0.75% nanoclay content yielded significant results, leading to a remarkable 391% increase in the UCS, a notable 58% reduction in dispersivity potential (DP), a 53% decrease in eroded soil mass, and a 29% decrease in the dispersive clay settlement after a 28-day curing period. Additionally, new exponential correlations were successfully developed between soil dispersivity and contact erosion parameters (CEPs) with high coefficients of determination using over 50 contact erosion test results. To facilitate the estimation of CEPs, the values were made dimensionless including the ratios of eroded soil mass (m/m0), settlement (S/H), and void ratio (ef-e0/e0). Finally, scanning electron microscopy (SEM) and microstructural image processing (MIP) confirmed the filling between soil particles and the reduction of the number of voids due to nanoclay incorporation into dispersive clays. [ABSTRACT FROM AUTHOR]

In the present study we investigated the combined effect of flow intermittence and wastewater treatment plant (WWTP) effluent on leaf litter decomposition in two Mediterranean streams with permanent and intermittent flow regimes. The litter decomposition experiment was performed using black poplar litter bags where we measured litter mass loss, fungal biomass, aquatic hyphomycete sporulation and species richness and C:N ratio. Afterwards, the remaining litter material from the different treatments was offered to the shredder Potamophylax latipennis in a microcosm laboratory experiment, and its growth and consumption rates were studied. We hypothesised that drying would decrease leaf litter decomposition in the permanent stream more than in the intermittent stream and that WWTP effluent would compensate for drying effects when both stressors interacted. The results indicated that drying has the greatest impact on the permanent stream, decreasing decomposition, aquatic hyphomycete species richness, and leaf litter quality. In the intermittent stream, WWTP effluent decreases aquatic hyphomycete species richness, but drying increases it, showing an opposing effect and a synergistic interaction. In the permanent stream drying provoked an increase in the shredder consumption rate. Thus, the expected more frequent intermittence in rivers under climate change may threaten the processing of organic matter. [ABSTRACT FROM AUTHOR]

Previous studies examining the influence of understory shrubs and light transmittance through the canopy (LT) (%) on seedling establishment of desired species and litter decomposition have reported inconsistent findings. Uncertainty still also remains about the effects of understory junipers (Juniperus oxycedrus L. subsp. oxycedrus) and LT on survival and growth of black pine (Pinus nigra Arnold.) seedlings as well as on litter decomposition across species' geographical range. Thus, this study aimed to examine the influence of understory junipers and LT on the growth and survival of black pine seedlings. Moreover, how junipers and LT affect litter decomposition was also monitored for eighteen months. Survival and growth of seedlings were most significantly affected by LT and understory junipers. LT and junipers negatively affected the survival of black pine seedlings. LT increased root-collar diameter (RCD) growth of the seedlings, while the RCD growth rate decreased with the presence of understory junipers. Moreover, the influences of LT and junipers on litter mass loss were mainly statistically significant; the presence of junipers and increasing LT in understory retarded litter decomposition. The findings may help our knowledge of ecological processes such as litter decomposition and seedling establishment in black pine forests. The results would also provide important guidance for evaluating the effects of overstory thinning (i.e., providing light to understory) and removing junipers on the ecological processes associated with litter decomposition and seedling recruitment in a black pine stand. [ABSTRACT FROM AUTHOR]

The high-speed penetration of concrete targets by kinetic energy projectiles results in apparent mass loss, which blunts the nose of the projectile and decrease its penetration performance. The friction work between the projectile and the concrete target, the plastic deformation of the projectile, and the cutting of aggregates to the projectile significantly affect the mass loss of the projectile. To address these effects, a discrete iterative model is developed for the mass loss and nose shape evolution of the projectile by coupling three mechanisms based on the effect of temperature on strength. In the model, both friction work and plastic work increase the temperature of the projectile’s surface layer, thereby weakening the strength of this part and rendering it easier for mass loss to occur due to aggregate cutting. The model discretizes the projectile and penetration process with respect to the space and time dimensions, respectively. The mass loss and nose shape evolution of the projectile are obtained by iteratively calculating a point-by-point regression. The predicted depth of penetration (DOP), mass loss, and residual projectile profile are compared with experimental data to validate the model. The comparison shows satisfactory agreement between the calculated results and experimental data. Additionally, the deceleration, velocity, DOP, and mass loss during penetration are analyzed with respect to time. Finally, based on the model, the effects of projectile strength, caliber-radius-head (CRH), and concrete target strength on penetration are discussed. [ABSTRACT FROM AUTHOR]

In this study, five surfactants containing two pyridinium groups and one of which has a carbon chain of different lengths were synthesized in order to counteract the corrosion that occurs more rapidly on the metal surface in acidic environment. By using spectroscopic methods (FT-IR and NMR), the products' chemical structures were verified. Gravimetric measurements were then applied to assess how well they resisted metal corrosion. The experiment involved immersing metal plates in 1.0 M HCl solutions with varying inhibitor concentrations for a day at room temperature. The weight loss of each plate was then measured. By utilizing these weight losses, both corrosion rate and corrosion inhibition efficiency were calculated. As a result of the calculations, it was realized that their ability to inhibit metal corrosion gradually increased due to the decrease in corrosion rates as the long carbon chain in their structure increased. However, in order to determine the type of adsorption on the metal surface, which is a factor directly affecting their corrosion inhibition, a Langmuir adsorption isotherm study was performed, which was found to be compatible. In order to visually support that they protect the metal surface against corrosion, 1600-fold magnified surface images of the metal surfaces removed from the corrosion test were taken with an optical microscope camera. [ABSTRACT FROM AUTHOR]

Corrosion is one of the major causes of metallic pipes deterioration used in irrigation, such as galvanized steel. Its magnitude is directly linked to the quality of the water flowed by these pipes. Thus, the use of cathodic protection combined with pipe coating is used to achieve a greater protection. This study aimed to evaluate the effectiveness of using cathodic protection by the sacrificial anode method to reduce the mass loss, related to corrosion, in specimens of galvanized steel caused by fertigation solutions containing urea or potassium chloride, at 10 g L−1, using Zn, Al and Mg anodes, in addition to a control treatment, without protection. For this, immersion tests were conducted to obtain the mass loss per area, by simulating 10 years of operation. The results showed that with the use of sacrificial anodes it is possible to reduce the mass loss in galvanized steel caused by potassium chloride solutions for fertigation; however, this type of cathodic protection may not be effective in protecting urea-containing solutions from overall corrosion. The aluminum anode is the most suitable to use in solutions with high electrical conductivity, as it can reduce the mass loss caused by potassium chloride by up to 78% compared to the unprotected treatment. [ABSTRACT FROM AUTHOR]

The decomposition of standing litter is a vital but easily neglected process. Most studies always focused on the decomposition of leaf litter on the surface of soil or sediment, whereas the decomposition of leaf and non-leaf litter in the air is often overlooked. A field experiment was conducted in the Yellow River Delta to investigate the decomposition of leaf and non-leaf (culm and sheath) litter (Phragmites australis) in the air and on the ground. The results showed that the litter on the ground decomposed faster than the standing litter due to its larger enzyme activities, and the remaining mass of litter on the soil surface was 73–87% of the standing litter. The culm litter had the largest mass remaining among three types of litter owing to the lowest enzyme activities and the largest initial C/N and C/P of the culm litter. Concerning the dynamics of nutrient, nitrogen and phosphorus in leaf and non-leaf litter were first released and then enriched at two decomposition interfaces. Of the three types of litter, the culm litter had the highest N remaining after 360 days of decomposition due to the largest initial C/N of the culm litter. Our findings emphasize the importance of standing litter decomposition in the wetlands of the Yellow River Delta, and suggest that the decomposition of non-leaf (culm and sheath) litter of emergent macrophytes should not be ignored in wetlands. [ABSTRACT FROM AUTHOR]

Given the immense threats of microplastics, we herein investigate photodegrading the debris of polyethylene bags (PBs) by sulfur-doped titanium dioxide. The optimization of operating parameters showed that controlling the water pH at 3 and introducing PBs by 0.10 g/L under a catalyst dose of 1.25 g/L reduced the polyethylene mass by 3.10% in 7 h, whereas raising the catalyst dose to 3 g/L improved the mass reduction to 4.72%. The extension of degradation time to 100 h at pH 3, catalyst dosage of 3 g/L, and PBs concentration of 0.10 g/L increased the mass loss ratio to 21.74%. Scanning electron microscopy of PBs after 100 h of photodegradation showed cracks on the surface accompanied by the increase of carbonyl index from 0.52 to 1.41 confirming the breakdown of the polymeric chain. Total organic carbon increased from 0.80 to 7.76 mg/L in the first 10 h of photodegradation, then decreased to 1 mg/L after extending the reaction time to 100 h due to the mineralization of organic intermediates generated from the photodegradation of PBs. Trapping tests exhibited the major role of hydroxyl radicals in the degradation system, and the catalyst showed high stability under five repetitive runs. This study proposes an efficient treatment system that can be implemented on a wider scale utilizing the synthesized catalyst to degrade plastics efficiently before their release to water streams. [ABSTRACT FROM AUTHOR]

Stars with initial masses in the range of 8–25 solar masses are thought to end their lives as hydrogen-rich supernovae (SNe II). Based on the pre-explosion images of Hubble space telescope (HST) and Spitzer space telescope, we place tight constraints on the progenitor candidate of type IIP SN 2023ixf in Messier 101. Fitting of the spectral energy distribution (SED) of its progenitor with dusty stellar spectral models results in an estimation of the effective temperature as 3091−258+422 K. The luminosity is estimated as lg(L/L⊙)∼4.83, consistent with a red supergiant (RSG) star with an initial mass of 12−1+2M⊙. The derived mass loss rate (6×10−6−9×10−6M⊙ yr−1) is much lower than that inferred from the flash spectroscopy of the SN, suggesting that the progenitor experienced a sudden increase in mass loss when approaching the final explosion. In the infrared bands, significant deviation from the range of regular RSGs in the color-magnitude diagram and period-luminosity space of the progenitor star indicates enhanced mass loss and dust formation. Combined with new evidence of polarization at the early phases of SN 2023ixf, such a violent mass loss is likely a result of binary interaction. [ABSTRACT FROM AUTHOR]

Samples with two different binary blended concrete mixes were prepared, one containing cement replacement of 50% slag (referred here as SL mix) and the other containing cement replacement of 20% fly ash (termed here as FA mix). The water to cementitious ratio used to produce concrete specimens was 0.41. On the top surface of each specimen, various reservoir lengths that ranged from 2.5 cm to 17.5 cm were fitted, and these reservoirs were filled with a 10% NaCl solution. Electromigration was used to accelerate the transport of chlorides, with an applied potential of 9 V at first, and subsequently reduced to 3 V after about a week. The electromigration was applied for a short period (few weeks to a couple of months). For a period of about 1100 days, the corrosion related parameters such as concrete solution resistance, rebar potential, and corrosion current were monitored via the rebar potential measurements, linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS) measurements, the latter used only to obtain the solution resistance. The corrosion current values determined through experimental observations were then converted to mass loss using Faraday's law. The readings of corrosion current values (last 7 sets of readings) as well as the calculated mass loss values were found to be larger for the rebars embedded in specimens prepared with SL mix, followed by rebars embedded in specimens prepared with FA mix. Corrosion current and calculated mass loss values in general tended to increase with increasing solution reservoir lengths. No cracks or corrosion products that reached the surface of the concrete were observed on the specimens for the duration of the reported monitored propagation period. This study offers a framework for future studies on accelerated steel corrosion in concrete. [ABSTRACT FROM AUTHOR]

Thermal runaway (TR) is one of the main concerns in battery application due to their hazard level for the people and environment. In this work, the thermal runaway behaviors of lithium-ion batteries (LIBs) are investigated in ambient nitrogen (N2) concentration from 78 to 100%. Several parameters are measured to assess the fire hazards of LIBs, including battery surface temperature (Tsurf), ignition time (tig), total mass loss, heat release rate, and total heat release. The experimental results show that the risk of TR increases with the increase in state of charge. For different N2 concentrations, the addition of N2 will reduce oxygen (O2) concentration and weaken internal reactions, while excessive N2 will react with lithium-ion inside the LIBs. 82% N2 concentration shows the greatest inhibition effect on TR, where the values of battery surface temperature, total mass loss, heat release rate, and the total heat release reach the minimum ones. [ABSTRACT FROM AUTHOR]

Modern industries utilize solar thermal energy in heat pump applications due to its enhanced performance and improved plant efficiency. The investigation presents the effective utilization of solar thermal energy in heat pump applications using different fluid pairs like zeolite/water, silica gel/water and alumina nanofluid/water. The effect of fluid pairs on heat transfer rate, thermal adsorption and mass loss of heat pump is monitored by STA Netzsch 409 differential thermogravimetric apparatus with a temperature range of 15–200 °C. The heat transformation of a heat pump is estimated by various water absorbed amounts of 0/1, 0/15, 0/20, 0/25, 0/30, 0/35 and 0/4 g/g under 0.005, 0.01, 0.05, 0.1, 1, 10 and 100% relative humidity. The result revealed that the alumina nanofluid-operated heat pump found higher thermal adsorption behaviour of 41.28W/m °C. The heat transfer rate of the alumina/water fluid pair was 117 kJ/mol. Different adsorption temperature points predict the saturation point of alumina at 0–200 min. [ABSTRACT FROM AUTHOR]

In this study, Zn-Ni-Cu and Zn-Ni-Cu-TiB2 were coated using a thermal spray (HVOF) process on a mild steel specimen. The coated specimens were characterized using Scanning Electron Microscope, Energy-Dispersive Spectroscopy, and x-ray-elemental mapping for surface morphology and coated powder distribution on the surface. The coated/uncoated mild steel specimens were tested for wear resistance using the pin-on-disc (ASTM G99-17) method. The wear volume loss of both coated Zn-Ni-Cu and Zn-Ni-Cu-TiB2 on mild steel was less as compared to uncoated mild steel. For understanding the adhesion strength of the coating with the substrate, the coated samples of Zn-Ni-Cu and Zn-Ni-Cu-TiB2 on mild steel were subjected to the scratch test. For Zn-Ni-Cu and Zn-Ni-Cu TiB2-coated mild steel the adhesion strength was higher as compared to uncoated mild steel inferring a strong bond between coating and substrate and least delamination. Hardness induced due to coating was tested using the Vickers hardness test and significant improvement in hardness was observed in coated samples of Zn-Ni-Cu and Zn-Ni-Cu-TiB2-coated mild steel compared to uncoated mild steel. For corrosion resistance of coatings in an acidic medium, a 0.5 M HCl immersion cycle test was performed using ASTM G1-03, and ASTM G-31, standards for 28 days (672 h). The weight loss for uncoated mild steel was much higher as compared to Zn-Ni-Cu and Zn-Ni-Cu-TiB2-coated mild steel. XRD analysis also confirmed the least forms of rust on the surface of coated samples compared to uncoated mild steel post immersion cycle test. EIS/Tafel analysis in 0.5 M HCl also revealed that both Zn-Ni-Cu and Zn-Ni-Cu-TiB2 on mild steel were anti-corrosive as higher corrosion potential and lower corrosion current density were observed compared to uncoated mild steel. The results in every test were quite motivating and proved that these coatings were both wear and corrosion-resistant. [ABSTRACT FROM AUTHOR]

This study mainly examines the slump, mass loss (ML), abrasion loss (AL), residual compressive strength (RCS), and residual splitting tensile strength (RSTS) of concrete reinforced with micro- and macro-polypropylene (PP) fibers after the F–T process. In the blends, micro- and macro-PP fibers were added to the blends at 0.3%, 0.6%, and 1% by volume. In total, 25, 50, 100, and 150 F–T cycles were applied to all samples. The study's results show that micro- and macro-PP fibers negatively affect the blends' slump values. Besides, PP fibers did not contribute to reducing the ML values of the samples after the F–T process. Moreover, the contribution of the PP fibers in prohibiting the decrease in RCS capacities of specimens after the F–T process is valid up to 0.3% volumetric fiber content. Additionally, PP fibers were more efficient in hindering reductions in AL and RSTS capacities after the F–T process of the specimens. Furthermore, using macro-PP fibers in hybrid form with micro-PP fibers reduced AL and improved RCS and RSTS capacities more than single macro-PP fibers. After 150 F–T processes, the reduction in AL of C0 control concrete was 9.41%, while the declines in AL of C1-C6 samples ranged from 7.56% to 8.92%. In addition, after 150 F–T processes, the decrease in RCS and RSTS loss of C0 control concrete is 25.09% and 28.30%. In contrast, the decline in RCS and RSTS loss of C1-C6 samples varies between 22.94–32.97% and 20.10–25.75%, respectively. [ABSTRACT FROM AUTHOR]

The results of studying the effect of thermal-treatment modes and finishing conditions on the rupture strength of woven-glass tapes and fiberglass fabrics and electrical insulation manufactured from them are reported. It is shown that the complete removal of the oiling agent "wax emulsion" from the surface of glass tapes is attained after stepwise thermal treatment at 250–400°C, but the rupture strength decreases by 80% in this case. The finishing of glass tapes with 3-glycidoxypropyltrimethoxysilane after the technical oiling agent is completely removed restores their rupture strength to the level of 35–40% of the initial value (before removing the wax-emulsion oiling agent) and makes it possible to create electrical insulation with water resistance to 1100 h at 23°C and to 7 h at 80°C. [ABSTRACT FROM AUTHOR]

The combined use of silica fume (SF) and single and hybrid-basalt (BA) fibers can be a prominent option in diminishing the degradations of concrete after freeze–thaw (F–T) effects. This study investigated slump, mass loss (ML), abrasion loss (AL), residual compressive strength (RCS), and residual splitting tensile strength (RSTS) of SF and single- and hybrid-BA fiber-reinforced concrete after F–T cycles. The results demonstrated that although using SF and BA fibers together adversely affected the workability of the mixtures, they significantly improved the samples' RCS and RSTS capacities. Besides, after F–T cycles, SF alone and with BA fibers are very efficient in reducing the AL of the samples. However, while using SF alone was somewhat effective in reducing the ML losses of the pieces, its use with single- and hybrid-BA fibers remained negligible. Furthermore, the hybrid use of BA fibers is more efficient in recovering concrete samples' workability and AL, RCS, and RSTS capacities than the single use. Compared to room conditions, after the 180 F–T cycles, the AL of the R0 control sample increased by 29.24%, while the SF and BA fiber-added R1–R7 samples ranged from 7.11% to 10.17%. Additionally, after the 180 F–T cycles, while the RSTS capacity of R0 control concrete decreased by 27.06%, the reduction in RSTS capacity of R1–R7 BA fiber-reinforced concrete ranged from 13.42% to 23.63%. This study is expected to constitute an important reference to the literature on how SF pozzolanic admixture and BA fiber additives play a role in improving the behavior of concrete against F–T cycles. [ABSTRACT FROM AUTHOR]

The results of the analysis of the activity of a solar type star G2V TOI-1422 are presented and estimates of the loss of atmospheric matter of the planet TOI-1422b are made. The planet can be attributed to the type of hot Neptunes. Compared to other exoplanets of a similar mass range, it is expected that the planet has an extensive gas envelope. According to the long-term photometric survey of Kamogata Wide-field Survey (KWS) the TOI-1422 activity was analyzed and the existence of possible activity cycles of 1650–1680 days and 2450 days was suggested. The probable value of the rotation period P of the star lies in the range of 27 (+19, –8) days, observations of the KWS survey in the V filter indicate the most possible value for the period P = 32 days. Mass loss of the planet's atmosphere is determined using an approximation formula corresponding to the model of atmospheric loss with an energy restriction. To estimate the flux of XUV photons analytical dependences were used linking the flux values and the parameter . Calculations have shown that the atmosphere matter loss of TOI-1422b is g/s; considering the existing errors in determining the parameters of the atmosphere it lies in the range from to g/s, and considering the uncertainty in the value of the chromospheric activity index—from to g/s. [ABSTRACT FROM AUTHOR]

Aims: Soil fauna is one of the major drivers of plant litter decomposition. This study aims to assess how soil fauna density and diversity may affect litter decomposition. Also, we assessed whether faunal communities inside the litterbags that are used to control the access of faunal groups or communities in ambient soils are better for predicting their effects on litter decomposition, given that soil fauna frequently move into and out of such litterbags. Methods: To answer this question, we synthesized 5336 observations extracted from 46 publications to assess the effects of soil fauna communities, their density and diversity on the rate of litter decomposition (k) and litter mass loss. Results: Results showed that (1) the presence of soil fauna significantly increased k by an average of 33.0% and that the effects were mainly controlled by initial litter concentrations of phosphorus and magnesium, (2) the density and diversity of soil fauna in litterbags significantly affected k and/or mass loss, but ambient communities had limited effects, and (3) the effects of soil fauna in litterbags on k were most significant during the early stages of decomposition (0 − 30% mass loss). Conclusions: Our study clearly showed that litterbag communities were better for predicting the effects of soil fauna on litter decomposition, and that their effects were most significant during the early stages of decomposition. These results improve our ability to estimate the contribution of soil fauna in liter decomposition and the associated carbon and nutrient cycling. [ABSTRACT FROM AUTHOR]

The ionic liquid 1-butyl-3-methylimidazolium dicyanamide ([Bmim][Dca]) is a novel solvent suitable for a wide range of applications in the petrochemical industry. However, the thermal safety of [Bmim][Dca] IL has not been fully considered when developing new uses, especially in areas involving high-temperature work. Starting from the initial decomposition temperature of [Bmim][Dca] IL, this article tries to find the highest temperature suitable for its intrinsic safety and provides a basis for its industrial production. The thermal stability of [Bmim][Dca] IL and its pyrolysis gas detection were obtained by simultaneous thermogravimetric analyser (STA) and thermogravimetric analysis coupled with Fourier infrared spectroscopy (TG-FTIR), respectively. Furthermore, the constant temperature experiments by STA show that the mass loss of [Bmim][Dca] IL at a specific temperature for 10 h is approximately 2% at 160 °C, about 15% at 190 °C, and more than 30% at 210 °C. The mass loss in the dynamic heating experiment is divided into two steps at each heating rate. The pyrolysis gas detection experiments by TG-FTIR show that extremely toxic gas such as HCN will be produced at 154 °C (T0.01/10 h). The real-time photography system by STA observed significant colour changes in samples at this temperature. Therefore, extrapolated temperature (TMOT,10 h,e) was defined to obtain a more accurate maximum operation temperature. Comparative experimental results show that the TMOT,10 h,e obtained by the extrapolation method has high reliability. The results of this study would provide a relevant basis for safer control based on the thermal hazard assessment of [Bmim][Dca] IL. [ABSTRACT FROM AUTHOR]

The decomposition of plant litter and animal dung is the key processes of nutrient cycling and has been studied in a wide range of grassland ecosystems. However, most studies focus on the separate processes of either plant litter or animal dung decomposition, while the interactions between these two processes, which occur in grazed grassland ecosystems, are rarely studied. We conducted an experiment in a semi-arid grassland in Central Inner Mongolia, to examine the mass loss rates and chemical composition changes of two plant litter species and three herbivore dung types separately or in combination over a 2-year period. Twenty litterbag treatments were used to represent 2 treatments of plant litter only, 6 treatments of herbivore dung only at two addition levels, and 12 treatments of litter and dung combinations. We found that horse dung had the biggest mass loss rate, followed by cattle dung and sheep dung, either separately or mixed with plant litter. Dung addition promoted the mass loss, nitrogen release and fiber fraction (hemicellulose, cellulose and lignin) loss of plant litter, and the promotion was strongest for cattle dung, weakest for sheep dung, and stronger at high dung addition levels and in the early stages. However, the effect of litter addition on dung decomposition, a negative effect, was significant only when the dung proportion was low in the litter and dung mixture (that is, in the treatment of 10 g litter + 6 g dung). Furthermore, a significant positive non-additive effect of mixing litter and dung on their total mass loss was detected for the mixture at a litter:dung ratio of 10:6, the ratio in the major grazing area of the grassland. Our findings suggest that mixture of herbivore dung with plant litter, as in actual grassland ecosystems, promotes litter decomposition, and the composition of the litter and dung in mixture, though it may inhibit dung decomposition, due to the changes in chemical stoichiometry of decomposing materials and biophysical microenvironment by the mixing. It is necessary to incorporate the non-additive effect of litter and dung mixture in modeling carbon and nutrient cycling of grassland ecosystems. [ABSTRACT FROM AUTHOR]

Through systematical experiment design, the physical blowing agent (PBA) mass loss of bio-based polyurethane rigid foam (PURF) in the foaming process was measured and calculated in this study, and different eco-friendly PBA mass losses were measured quantitatively for the first time. The core of the proposed method is to add water to replace the difference, and this method has a high fault tolerance rate for different foaming forms of foams. The method was proved to be stable and reliable through the standard deviations σ1 and σ2 for R1 (ratio of the PBA mass loss to the material total mass except the PBA) and R2 (ratio of the PBA mass loss to the PBA mass in the material total mass) in parallel experiments. It can be used to measure and calculate the actual PBA mass loss in the foaming process of both bio-based and petroleum-based PURF. The results show that the PBA mass loss in PURF with different PBA systems is controlled by its initial mass content of PBA in PU materials ω. The main way for PBA to dissipate into the air is evaporation/escape along the upper surface of foam. This study further reveals the mechanism of PBA mass loss: the evaporation/escape of PBA along the upper surface of foam is a typical diffusion behavior. Its spread power comes from the difference between the chemical potential of PBA in the interface layer and that in the outside air. For a certain PURF system, R1 has approximately linear relationship with the initial mass content of PBA in PU materials ω, which can be expressed by the functional relationship R1 = kω, where k is a variable related to PBA's own attributes. [ABSTRACT FROM AUTHOR]

To assess the resistance of polymer nanocomposites to the effects of atomic oxygen in low Earth orbits, we study the effect of oxygen plasma on the structural and optical properties of an epoxy resin with the addition of graphene and Taunit-M carbon nanotubes. Introducing carbon fillers to epoxy resin increases the weight loss and erosion depth when exposed to oxygen plasma. The weight erosion coefficient at an atomic-oxygen fluence of 30 × 1020 cm–2 is 0.82 × 10–23 g/at for pure epoxy resin and 0.86 × 10–23 and 1.06 × 10–23 g/at for samples with graphene and Taunit-M, respectively. In the case of the sample with the Taunit-M filler, a greater weight loss and erosion depth are observed as a result of irradiation in oxygen plasma in comparison with the sample with the graphene filler. The treatment of carbon nanocomposites in oxygen plasma significantly decreases the reflectance coefficients in the spectral range of 0.2–2.5 µm. The lowest diffuse (less than 1%) and specular (less than 0.02%) reflectance coefficients are registered for the irradiated polymer with Taunit-M. [ABSTRACT FROM AUTHOR]

Background: Manganese (Mn) is believed to be a key variable controlling litter decomposition, especially in the late stage. However, the direct effects of Mn on litter decomposition and litter mixing effects during decomposition have been rarely tested in subtropical forests. Methods: We collected leaf litter of four common tree species (two broadleaf tree species, Liquidambar formosana and Schima superba; two coniferous tree species, Pinus massoniana and Pinus elliottii) from subtropical plantations of southern China, and used a field Mn addition experiment to assess the impact of Mn on single and mixed litter mass loss during 780-day decomposition. In addition, we measured soil nutrient availability and hydrolytic enzyme activities. Results: Despite unchanged soil nutrient availability, Mn addition generally increased soil β-1,4-glucosidase, cellobiohydrolase, leucine aminopeptidase, and acid phosphatase activities. Irrespective of litter types, Mn addition did not affect litter mass loss in the early stage (mass loss <40%) but enhanced litter mass loss in the late stage (mass loss >40%). During mixed litter decomposition, synergistic effects were more common for coniferous litter than for broadleaf litter. Moreover, Mn addition reduced the magnitudes of synergistic effects on litter decomposition and even changed synergistic effects to additive effects. Thus, the positive effect of Mn addition on litter decomposition was greater for single litter (18%) than for mixed litter (6%). Conclusions: Mn availability is crucial for leaf litter decomposition in the late stage rather than in the early stage, and Mn addition influences mixed litter decomposition by reducing non-additive effects in subtropical plantations. [ABSTRACT FROM AUTHOR]

The decomposition process in the forest ecosystem is regulated by environmental conditions, the chemical nature of litters, and microbial activities. We aim this study to understand the weight loss rate, nutrient release, and controlling factors of fine root decomposition in lower tropical forest (LTF) and upper tropical forest (UTF) of Nepal Himalaya. The nylon net bag technique was used to determine the decomposition rate of the fine root. Five gram air dried samples of < 2 mm and 2–5 mm size class fine roots were kept in nylon net bags and buried at 0–10 cm soil depth in each forest. Bags were recovered from both forests after 60, 120, 180, 240, 300, 365, 425, 485, and 545 days of sample placement and preceded for the estimation of weight loss and nutrient analysis. Initially, the weight loss was fast up to 120 days followed by a slow decomposition rate from the middle to the last phase of the experiment in both forests. At the 365 days of experiment, weight loss in < 2 mm fine root was 12.67% faster in LTF than UTF, while that in 2–5 mm sized root was 21.05% faster in LTF than UTF. An increase in nitrogen and phosphorus concentrations in the residual materials is accompanied with weight loss of fine root. At the end of experiment, the release of nitrogen (N), phosphorous (P), and potassium (K) in both sized roots was faster in LTF than UTF. The N, P, and K release rates in LTF were 11.36, 8.88, and 3.09% faster than UTF in less than 2 mm root size, and 17.10, 10.25, and 6.38% faster in 2–5 mm root size, respectively. The belowground input of nutrients through fine root plays a significant role in nutrient accumulation in soil which contributes to increase the entire forest production. [ABSTRACT FROM AUTHOR]

Purpose: To assess the direction and strength of climate and leaf litter trait effects on decomposition dynamics throughout the litter decomposition process. Methods: We performed a three-year-long litterbag translocation experiment along an elevational gradient in a transitional mixed forest in China. We explored temporal shifts in the relative contribution of microclimate and litter traits of seven dominant species to mass loss throughout the decomposition process. Results: Air temperature and soil moisture imparted no significant effects on mass loss in the initial decomposition stage (0–6 months) but exerted positive effects after 6 months' incubation (p < 0.05). Initial specific leaf area (SLA) was positively associated with mass loss only during the early decomposition stages (0–12 months). Litter P concentration was positively while N concentration was negatively associated with mass loss for almost all decomposition stages. Both litter Mg and Ca concentrations were negatively associated with mass loss throughout the whole decomposition process (p < 0.05). The relative contribution of microclimate was weaker than that of litter traits during the early stages but increased in the late decomposition stage (after 36 months). SLA and Mg were the most important traits during the early stages (0-12 months), whereas N and Mg were relatively stronger during the later stages (30–36 months). Conclusion: Our results have highlighted that microclimate (particularly temperature) exerted dominant control over later-stage litter decomposition. Often-overlooked litter traits such as Mg, are key potential drivers of litter decomposition dynamics and should be more explicitly incorporated into current biogeochemical models to better understand litter-driven nutrient and carbon cycling. [ABSTRACT FROM AUTHOR]

This study provides the firsthand corrosion data of Grade 40 #3 and #4 deformed steel rebars that had been exposed to saltwater environment for 20 years under service load. Cross-sectional area loss and mass loss were measured. The mechanical and physical properties were investigated experimentally. The results were compared with fresh specimens and previously published results. The cross-sectional area loss and mass loss showed comparable results with the experiments on specimens suffering from long-term chloride ingression in the existing literature works. The tensile stress–strain behavior was also found to be similar to the previous research on corroded rebar from reinforced concrete structure under service load. The data from physical and mechanical investigation will be helpful to realistically estimate the long-term corrosion damage of rebars in reinforced concrete structures exposed to the marine environment. The influence of strain aging phenomena of corroded rebar on the mechanical and fracture behavior is also discussed in the paper. These effects need to be considered for capacity prediction and factor of safety estimation of corroded reinforced concrete structures. [ABSTRACT FROM AUTHOR]

Recently, increasing attention has been focused on prediction models for quality changes of fresh produce based on mass-loss values. In this study, we applied a virtual distribution treatment (a 2-day transportation period followed by a 7-day storage period) of tomato fruit, and the effects of transportation temperature (0, 5, 10, and 20 °C) on fruit mass loss and color (a* values) of stored green, pink, and red tomatoes at 10 °C were investigated. In addition, the relationship between fruit mass loss and a* values during the virtual transportation treatment were analyzed. The virtual transportation at 0–5℃ was effective in inhibiting mass loss in green and pink tomatoes. Further, an excess increase in mass loss due to chilling injury was confirmed in red tomatoes at 0 °C; however, this phenomenon did not occur at 5 °C. Presumably, tomato chilling injury is reversible for a temperature-dependent period. The a* values of the green and pink tomatoes increased gradually at high temperature. The changes in a* values and the extent of fruit mass loss were recorded for green and pink tomatoes, and linear regression analysis allowed the changes in a* value to be predicted from the mass loss data with a high degree of accuracy (R2 = 0.89–0.91). [ABSTRACT FROM AUTHOR]

Background: Despite the importance of root decomposition in predicting ecosystem responses to future climate change, the effects of branch order on root decomposition and the feedback to soil still remains poorly understood. Here we separated root samples taken from two tree species (Castanopsis fargesii and Schima superba in subtropical forests along the coastal area in eastern China) into four-order classes (1st–2nd order, 3rd order, 4th order, and 5th order) and conducted a 540-day litterbag incubation experiment in laboratory to examine root mass loss, nutrient release, and the influence on soil during decomposition. Results: C. fargesii roots of 1st–2nd and 3rd order decayed more slowly than those of 4th and 5th order, but this pattern was not significant for S. superba. Of all the measured root traits, the decomposition rates correlated best with root C/N ratio, diameter and specific root length (SRL) based on the structural equation modeling. Both tree species and root order exhibited significantly effects on root initial traits. Overall, C. fargesii roots decay faster than S. superba, and this appears to be associated with root initial C quality and N concentration. In addition, root order positively affected root decomposition rates mainly through root diameter and SRL. However, no significant difference was found in C and N content between soils below the litterbag with different-order roots. Conclusions: Our findings suggest the effects of branch order on root decomposition are dependent on tree species. Moreover, root morphological properties might also be the controlling factor in root decay besides root chemistry fractions. Overall, the integrative effects should be considered to improve our understanding of the fate of fine-root litter and their contribution to soil C and N pool. [ABSTRACT FROM AUTHOR]

Based on the turbulent convection model, we propose new energy named turbulent thermal energy to explain the observed mass loss, and correspondingly propose a modified criterion on mass loss. We obtain the mass-loss rates and make a test of the proposal for the RGB and EAGB stars. The results coincide with the observational data, and also agree with the results of some other semi-empirical formulae based on the fundamental stellar parameters. [ABSTRACT FROM AUTHOR]

In this study, the strength reduction of high-strength concrete (HSC) integrating silica fume (SF) and nano-silica (NS) exposed to elevated temperatures besides its mass loss is evaluated. Cubes and cylinders were cast and tested at 28 and 56 d to evaluate the concrete compressive and tensile strengths (fcu and ftu), respectively. The prepared cubes and cylinders were subjected to elevated temperatures (T = 200, 400, 600, 800, and 1000 °C), cooled in air, and tested in compression and tension, respectively. For the cement paste and aggregate, spot analysis was performed through scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). Furthermore, SEM between aggregate and cement paste was performed. The obtained results indicated that for concrete mixes incorporating NS, compressive strength increased as temperature was raised to 400 °C and decreased as temperature increased from 400 to 800 °C. In addition, a remarkable reduction in the concrete tensile strength was observed up to T = 800 °C. At T = 1000 °C, all specimens were destroyed. Moreover, the lowest Ca/Si ratio was observed for the NS mixes according to the EDS spot analysis results. The mass loss of the concrete mixes integrating SF was higher than that of the mixes integrating both SF and NS except at 800 °C. Finally, a detailed review of the effect of macro and nanomaterials on the concrete properties was presented. [ABSTRACT FROM AUTHOR]

Building structures can suffer from mechanical, physical and chemical pathologies. One of the serious hazards that can drastically reduce the service life of concrete structures is fire or high temperatures. The use of fine additive materials (FAM) can be a good way for enhancing the fire resistance of concrete. This paper aims to produce an eco-efficient and cheaper self-compacting mortar (SCM) that has a sufficient resistance to high temperatures, by replacing a part of cement with powders from recycled materials, such as glass and ceramic. Nine mixtures were prepared and tested, one as reference mix and eight containing, separately, different proportions in mass of ceramic and glass powders with 5, 15, 25 and 50%. In order to study the behavior of SCM at high temperatures, a total of 135 specimens of 40 × 40 × 160 mm were cast and left cured for 28 days and then subjected to different temperatures (400 °C, 600 °C, 800 °C and 1000 °C) for 2 h. The degradation was assessed by measuring the loss of mass, compressive strength, flexural strength and ultrasonic pulse velocity (UPV) for each temperature. Under conventional temperature, both of compressive and flexural strength and UPV decreased with introducing ceramic and glass powders. The optimal percentage use of ceramic and glass powders under fire conditions is 5%. This percentage can be increased to 15% or 25% to obtain SCM with acceptable mechanical and physical properties. The replacement of 50% of cement with glass powder caused a significant reduction in the mechanical performance of SCM mixture compared to ceramic powder at the same percentage. [ABSTRACT FROM AUTHOR]

The presence of salts during cyclic wet and dry conditions can cause weathering of rock and is the main cause of damage to ancient and modern buildings. Accordingly, salt weathering, especially of granite, has aroused great interest. Determining the relationship between wet–dry cycling and the physical properties of rock is of great significance to geotechnical engineering. In this paper, granite samples were processed into two shapes (round and semicircular) and subject to 0, 10, 20, 30, 40 and 50 wet–dry cycles, with the wetting achieved with 0%, 5%, 10% or 20% concentrations of Na2SO4 solution. The mass loss, roughness and indentation hardness of granite samples all changed to some extent with cycle number, with greater changes occurring at higher salt concentrations. Rock shape also affects the extent of weathering damage, as surface area and features such as corners facilitate the ingress of salt solution. [ABSTRACT FROM AUTHOR]

Water inrush disasters in coal mines and tunnels are mostly related to fractured zones, which not only cause great economic losses and casualties but also seriously affect coal mine production. Therefore, research on the mechanism of water inrush is an urgent need for the coal-mining industry, which should be carried out effectively to prevent the occurrence of water inrush. Due to the excavation activities, the rock mass in the fractured zone is prone to structural deformation and fractured, and the non-Darcy seepage occurs with particle migration and structural deformation, i.e., seepage suffusion happens. With the continuous development of seepage suffosion, the seepage field of rock mass changes, which is very easy to cause non-Darcy seepage instability, which is the essence of seepage suffosion. This paper describes the seepage suffosion and the non-Darcy seepage instability of the broken rock mass, distinguishes the related concepts, and reviews the research progress. Though previous studies have creatively given some criteria from many angles, for instance, βk2 < 3.90 × 10−12 m3, r < 4.90%, m p ′ ≥ 100 gs−1 m−3, etc., it was not enough to solve the related engineering problems. Because the mining activity in the rock mass is a complex physical and mechanical process, solid, liquid, and gas coexist under the coupling action of multiple fields, such as the stress field, temperature field, and seepage field. Therefore, it proposes that, in the further study of water inrush mechanism, (1) the stable/unstable deformation, the failure state, failure conditions, and failure laws of rock mass under the coupling action of stress, groundwater, gas, temperature, etc. are necessary to be fully considered; (2) the non-Darcy seepage process needs to be described in suitable theory; (3) more disciplines and more advanced methods need to be integrated and adopted; (4) simpler judgment methods and accurate judgment standards need to be put forward. It helps to penetrate the mysteries of water inrush disasters in the coal mines and tunnels with fractured zones. [ABSTRACT FROM AUTHOR]

Slower leaf litter decomposition rates for trees associated with ectomycorrhizal (ECM) fungi compared to arbuscular mycorrhizal (AM) fungi may lead to the development of conservative nitrogen cycling and accumulation of soil organic matter in surface soils of ECM-dominated forests. Slower decomposition is hypothesized to occur via two often-confounded mechanisms: production of lower quality litter by ECM-associated trees compared to AM-associated trees and competition for nitrogen between ECM and saprotrophic decomposers in ECM-dominated stands. To disentangle the effects of litter quality and stand mycorrhizal type on decomposition, we measured litter mass loss rates of two AM species higher and two AM species similar in chemical quality to two ECM species. Leaf litter was decomposed for two years in neighboring ECM- and AM-dominated stands of a wet tropical montane forest. Litter phosphorus (P) was the strongest predictor of decomposition rates across all species, with no effect of litter mycorrhizal type on decomposition rates. Only one species, which exhibited intermediate litter chemical quality and decomposition rate, decomposed significantly faster in AM- compared to ECM-dominated stands. Leaf litter decomposition rates cannot be predicted directly from litter mycorrhizal type or stand mycorrhizal type because litter chemical quality and environmental conditions mediate the manifestation of slower decomposition in ECM stands. [ABSTRACT FROM AUTHOR]

During the past decades, glacier mass loss is becoming increasingly significant worldwide but knowledge about the acceleration is still limited despite its potentially profound impacts on sea level rise, water resources availability and glacial hazards. In this study, we analyzed the acceleration of glacier mass loss based on in-situ measurements and on the latest compilation dataset of direct and geodetic observations for the period 1961–2016. The results showed that the rate of glacier mass loss has increased worldwide during the past decades. At the global scale, the rate of glacier mass loss has been accelerating at 5.76±1.35 Gt a−2 as well as 0.0074±0.0016 m w.e.a−2 on mass balance (refer to the area-averaged mass change value) during the whole period. At regional scales, for mass change rate, the heavily glacierized regions excluding Antarctic and Subantarctic exhibited a larger acceleration compared to other regions. The highest acceleration of mass change was found in Alaska glaciers (1.33±0.47 Gt a−2) over the full period. As for mass balance, high acceleration occurred on the regions with small glaciers as well as on the heavily glacierized regions. Central Europe exhibited the highest acceleration (0.024±0.0088 m w.e.a−2) during 1961–2016. High level of consistency between the acceleration and temperature implies that climate warming had a significant effect on the accelerating of glacier mass loss. Moreover, acceleration of the contribution from the Greenland ice sheet (0.028 to 0.070 mm a−2) and Antarctic ice sheet (0.023 to 0.058 mm a−2) to sea level rise exceeds acceleration of the contribution from global glaciers (0.019±0.013 mm a−2). These results will improve our understanding of the glacier retreat in response to climate change and provide critical information for improving mitigation strategies for impacts that may be caused by glacier melting. [ABSTRACT FROM AUTHOR]

Purpose: Ultraviolet (UV) radiation plays an important role in litter decomposition, but the direction and magnitude of its effect remain inconsistent. Materials and methods: To determine the responses of litter decomposition and C and nutrient release to UV radiation, a meta-analysis that comprised 544 observations in field experiments was performed. Results and discussion: The change in UV radiation had significant effects on litter mass loss and litter nitrogen (N) and phosphorus (P) release in field studies, and litter types affected only the magnitude of UV radiation changes on mass loss and nutrient release. In addition, mass loss and nutrient release varied as the decomposition process continued: UV enhancement accelerated litter decomposition only after 4 months of decomposition, whereas the effect of UV attenuation on litter decomposition decreased with decomposition time. The inhabitation of UV attenuation on litter decomposition increased with a decrease in precipitation. Conclusion: Overall, the different responses of mass loss and nutrient release in litter decomposition to changes in ultraviolet radiation may cause different C and nutrient cycling in terrestrial ecosystems in the Southern Hemisphere and Northern Hemisphere. [ABSTRACT FROM AUTHOR]

The conditions under which auto-extinction of timber can occur are of particular importance for mass timber structures where elements of structural timber are exposed, or become exposed, during a fire. Using experiments on 95 mm cubes of timber, the sensitivity of auto-extinction to sample orientation, and an imposed flow across the surface of the sample was investigated. It was found that the variation in burning rate between the vertical and horizontal orientation was 8% but that, for samples in a vertical orientation, auto-extinction occurred at a higher value of mass loss. It was found that while the critical mass loss rate for extinction was relatively consistent in a given orientation (coefficient of variation, 16%), the variability in the time to extinction, and thus the total mass of timber consumed, was significant (coefficient of variation, 40%). Critical mass loss for extinction was linked to the square of the flow velocity at the surface of the sample. [ABSTRACT FROM AUTHOR]

Disc cutters are the dominant cutting tools used in tunneling by rock TBMs. During the operation, disc cutters wear out and should be replaced with new ones. The wear rate of the disc cutters can be defined in terms of rolling distance/time and volumetric wear. Furthermore, the wear rate can be attributed to the mass loss. The wear prediction models for disc cutter have been developed on the basis of the intact rock abrasion indices, most commonly Cerchar abrasivity index (CAI). Examination of these models and comparing their results with actual wear observed in the Kerman water conveyance tunnel (KWCT) project show that the available models are conservative. In other words, reliance only on the intact rock abrasion does not offer an accurate prediction of the wear rate of the disc cutter. Therefore, rock mass conditions should also be considered in the calculations. The current study shows that volumetric mass loss is a more appropriate method to predict wear life of disc cutters due to consideration of various geometric parameters such as spacing between disc cutters, penetration rate, installation radius, and bored length. Subsequently, a new empirical prediction model is proposed by nonlinear multivariable regression based on CAI as a rock material parameter and RQD (rock quality designation) as a rock mass parameter to estimate the cumulative volumetric mass loss of disc cutters. For ease of using the model, a chart is introduced that determines the wear on the disc cutters based on the CAI and RQD. [ABSTRACT FROM AUTHOR]

An approximate analytical solution to the equations of the physical theory of meteors is obtained for a meteoroid moving as a single body under the assumption of constant ablation parameter. The approach allows predicting the velocity and mass of the meteoroid at any point of its trajectory. The accuracy of the solution is estimated. A numerical-analytical method for solving the equations is proposed for the case when the ablation parameter is variable. The soluitons obtained by different methods with constant and variable ablation parameters are compared. [ABSTRACT FROM AUTHOR]

Invasive terrestrial isopods are likely to have altered leaf litter decomposition processes in North American forests, but the mechanisms underlying these alterations and the degree to which they differ among isopod species are poorly characterized. Using mixed-deciduous leaf litter microcosms, we quantified the effects of two common, invasive isopods (Oniscus asellus and Porcellio scaber) on short-term leaf litter decomposition and microbial community structure and function. Microcosms containing ground litter and a microbial inoculant were exposed to one of the two isopod species or no isopods for 21 days. Mass loss was then quantified as the change in litter dry mass after leaching, and microbial respiration was quantified as the mass of CO2 absorbed by soda lime. Litter leachates were plated on agar to quantify culturable bacterial and fungal abundance, and denaturing gradient gel electrophoresis of amplified leachate microbial DNA was used to characterize shifts in microbial community structure. Isopod presence increased litter mass loss by a modest ~ 6%, but did not affect litter microbial respiration. Bacterial abundance increased significantly in the presence of isopods, while fungal abundance was either unchanged or reduced. Overall litter microbial species richness was reduced by isopods, with O. asellus specifically reducing fungal abundance and diversity. Isopods modified the microbial community structure by suppressing four bacterial and one fungal species, while promoting growth of four other bacterial species (two unique to each isopod species) and two fungal species (one which was unique to O. asellus). [ABSTRACT FROM AUTHOR]

The previous researches on the degradation process of concrete under sulfate attack mainly focus on non-damaged concrete. It may lead to an excessive evaluation of the durability of the structure, which is detrimental to the safety of the structure. In this paper, three different damage degrees of concrete specimens with non-damaged (D0) and initial damage of 10% (D1) and 20% (D2) were prefabricated and subjected to sulfate attack and wetting–drying cycles. With the increase of sulfate attack cycles (0, 30, 60, 90, 120, 150 cycles), the changes in mass loss, relative dynamic modulus of elasticity, and the stress–strain curve were studied. The results show that the mass of the D0 specimen had been increasing continuously before 150 sulfate attack cycles. The mass of D1 and D2 had been increasing before 60 cycles, and decreasing after 60 cycles. At 150 cycles, the mass loss of D0, D1, D2 were − 1.054%, 0.29% and 3.20%, respectively. The relative dynamic modulus of elasticity (RDME) of D0 specimen increases continuously before 90 sulfate attack cycles. After 90 cycles, the RDME gradually decreases. However, for D1 and D2 specimens, the RDME began to decrease after 30 cycles. The damage degree has an obvious influence on the compressive strength and elastic modulus. For the D0 specimen, the compressive strength and elastic modulus increased continuously before 90 cycles and decreased after 90 cycles. The compressive strength and elastic modulus of D1 and D2 specimens began to decrease after 30 cycles. The stress–strain curves of concrete with different initial damage degrees were established, and the fitting results were good. Finally, based on the analysis of experimental data, the degradation mechanism of concrete with initial damage under the sulfate wetting–drying cycle was discussed. [ABSTRACT FROM AUTHOR]

To analyze the strain-based non-Darcy permeability properties in crushed rock accompanying mass loss, a self-designed seepage testing system for crushed rock accompanying mass loss is adopted. Based on the collected lost mass and time series of seepage velocity and the pressure gradient, permeability parameters and strain are obtained. Time-dependent characteristics of permeability parameters and strain are divided into three stages. Permeability and strain increase while non-Darcy flow β factor and acceleration coefficient decrease with seepage process lasting. Exponential functions between permeability parameters and strain are established, where strain is the volumetric strain, being in good agreement with conclusions drawn by scholars before. The coefficients of exponential functions are analyzed combining with the lost mass ratio. It shows that a greater mass loss leads to a larger permeability, inducing the greater possibility of water inrush; samples with the lost mass ratio less than 5% have the least water inrush possibility. [ABSTRACT FROM AUTHOR]

The paper presents the results obtained for the distribution of heat flux incident upon a refractory plate of a hypersonic flight vehicle moving at space velocities at various distances from the Earth's surface. The paper also provides the results of studying phase transitions in the near-wall boundary layer occurring during the hypersonic flow over the ablating surface. The effect of the catalytic wall on heat flux is analyzed. The emphasis is on the analysis of mass loss from the surface of high-velocity flight vehicles based on detailed consideration of the mechanism of heterogeneous catalytic reactions taking place under the surface mass transfer conditions. A temperature distribution is provided across the thickness of the boundary layer at the stagnation point of a blunt-nosed body with a refractory coating for a specific section of the flight path. The mass loss from the surface of crystalline refractory bodies is determined. [ABSTRACT FROM AUTHOR]

Mass migration and loss in fractured rock during seepage processes are considered to cause seepage instabilities, which can lead to seepage catastrophes. In this study, the migration and loss of fine particles in fractured rock during seepage are theoretically and experimentally investigated. We analyze the characteristics of lost and migrated mass obtained from the experiments over time, as well as the effect of initial compression. A linear relationship is found to best describe the difference of migrated versus lost mass and Talbot power exponent (TPE), with the slope and intercept related to initial compression. The lost and migrated mass are described mathematically based on the TPE and initial compression. We quantify the behavior of mass migration and loss, which allows calculation of the possibility of seepage instability and water inrush. A seepage instability occurs if the lost mass ratio is greater than 4.90%. The results presented here provide important insight into the water inrush mechanism in geotechnical engineering applications. [ABSTRACT FROM AUTHOR]

A general approach to modeling the mass loss of polymer composites under space conditions is proposed. The case of the effect of radiation-stimulated evaporation on the mass loss of the polymer composite in vacuum upon irradiation with 10–50 keV electrons is considered in detail. It is shown that the energy loss and density of the electron flow, as well as the mass fraction of the filler in the material, affect the mass loss of the polymer composite. In particular, it is found that the mass loss of the studied materials when irradiated in vacuum at a fixed density of the radiation energy flux decreases with increasing electron energy Е0. This is explained by the fact that the smaller Е0, the greater the stopping power; therefore, in larger quantities and in a thinner surface layer of the material, radiolysis products are produced. In this case, the gas permeability of the irradiated layer of the material grows with the energy absorbed in it, and the products of radiolysis are released into the vacuum more quickly. It is established experimentally that, at φ = 1011 cm–2 s–1, the mass loss of the materials studied occurs mainly via radiation-stimulated gas release, and at φ = 1012 cm–2 s–1 and the value of Е0 = 10 keV, the weight of the evaporated material in the total loss mass of polymeric material is more than 50%. [ABSTRACT FROM AUTHOR]

Little is known about the effect of woody plant expansion on decomposition of root mixtures in grass-dominant temperate wetlands. Here, we collected fine roots (< 1 mm) of Deyeuxia angustifolia (grass) and Betula fruticosa (shrub) from a freshwater wetland in the Sanjiang Plain, Northeast China, and decomposition rates of their monocultures and mixtures (with 2:1 and 1:2 mass ratios) were determined by measuring carbon (C) mineralization and mass loss with a 365 days incubation experiment. Meanwhile, litter mixing effects were assessed by the differences in observed decomposition rates of root mixtures and predicted values based on the performance of component species decomposing alone. Betula fruticosa fine roots had higher N, total polyphenol, and condensed tannin concentrations than D. angustifolia fine roots. By the end of incubation, B. fruticosa fine roots generally had greater C mineralization rate and mass loss than the other three root treatments. Notably, both C mineralization rate and mass loss were lower than the expected values in the B. fruticosa-dominant mixture, whereas there were no significant differences between observed and expected values in the D. angustifolia-dominant mixture. Our findings imply that the increase in woody plant abundance will exert influences on fine root decomposition rates through altered substrate quality and litter mixing effects in grass-dominated temperate wetlands. [ABSTRACT FROM AUTHOR]

Litter decomposition in forests is affected by tree species composition which produces litters with specific characteristics and alters soil surface conditions and nutrient availability. The impact of such changes in soil microsite conditions on litter decomposition is however poorly elucidated. We studied the decomposition of sugar maple leaves in 22 plots varying from pure hardwoods to mixedwoods to conifer-dominated stands across four sites in the sugar maple bioclimatic domain in Quebec. Mass loss and nutrient release were assessed over a 2-year experiment. Proxies of moisture availability measured under the canopy were more valuable for explaining the variability in leaf litter decomposition rates than soil temperature, litter quality and general site measurements (e.g. air temperature, rainwater). Throughfall amounts and soil volumetric water content (VWC) explained 56% of the variability in mass loss constants. Sugar maple leaf litter under hardwoods also decomposed more rapidly than under conifer-dominated stands. Slower litter decomposition under conifer-dominated stands was again more largely controlled by the lower soil VWC than the more acidic forest floor created by the needles. This study highlights that proxies of moisture availability measured at the microsite level can be key variables to predict litter dynamics in forests. [ABSTRACT FROM AUTHOR]